Reinventing the Planet

_PI: Tim Lenton (University of Exeter)

Team: 7 institutions, 7 academics, 3 postdocs, 3 PhD students

__Short introduction of the project: The Earth is truly a remarkable planet. In addition to the physical
processes driving plate tectonics, climate and ocean-atmospheric
exchange, it supports an extraordinary diversity of living organisms,
from microbes to mammals and everything in between. Such wasn’t always
the case, however, and it is clear that both the planet and its
biosphere have evolved – indeed, co-evolved – over deep time. In the
past two billion years, by far the most fundamental shift in this
co-evolutionary process occurred during the Neoproterozoic (1000 – 542
million years ago), a planetary revolution that culminated in the
modern Earth System. The Neoproterozoic begins with a biosphere
populated almost exclusively by microbes, and ends in the midst of its
greatest ever evolutionary radiation – including the diverse
macroscopic and biomineralizing organisms that define the modern
biosphere. At the same time, it witnessed the greatest climatic and
biogeochemical perturbations that the planet has ever experienced,
alongside major palaeogeographic reconfigurations and a deep ocean
that is becoming oxygenated for the first time. There is no question
that these phenomena are broadly interlinked, but the tangle of
causes, consequences and co-evolutionary feedbacks has yet to be
convincingly teased apart. In order to reconstruct the Neoproterozoic
revolution, we propose a multidisciplinary programme of research that
will capture its evolving geochemical and biological signatures in
unprecedented detail. Most significantly, these collated data will be
assessed and modeled in the context of a co-evolutionary Earth
system., whereby developments in one compartment potentially
facilitate and escalate those in another, sometimes to the extent of
deriving entirely novel phenomena and co-evolutionary opportunities.

Photo by. Y. Shields-Zhou

Our newly launched collaborative project will be guided by three general hypotheses, testable against accruing data and theory: H1) that the enhanced weathering associated with land-dwelling eukaryotes was initiated in the early Neoproterozoic leading to major environmental change, including extreme glaciations and stepwise increase(s) in atmospheric oxygen concentration; H2) that major environmental changes in the mid-Neoproterozic triggered the emergence of animals; and H3) that the late Neoproterozoic-Cambrian radiations of animals and biomineralization were themselves responsible for much of the accompanying biogeochemical perturbations. Primary data for this project will be assembled from field studies of key geological sections in the UK and North China, along with contributed sample sets from Namibia, Spitsbergen and various archived collections. Together, these offer close to comprehensive coverage of the Neoproterozoic, and highlight the sometimes overlooked British Neoproterozoic heritage of well preserved non-marine successions of the Torridonian in Scotland and spectacular new surfaces of Ediacaran macrofossils from Charnwood Forest. Collected samples will be analysed to assess associated weathering and climate (Sr, C, O and S isotopes), oceanic redox conditions (Fe speciation and trace metals), nutrient dynamics (P speciation and trace metals) and biological constituents (microfossils, macrofossils and biomarker molecules). These data will be integrated and interrogated through the development of heuristic, spatial and evolutionary models. Beyond its integrative approach, the potential of this project lies in the diversity of the contributing researchers from the fields of Neoproterozoic stratigraphy, geochronology, biogeochemistry, palaeobiology, Earth system modeling and biomarker analysis. Further insight will come from our contingent of two PDRA’s and three PhD students working across a range of topics and linked via a schedule of regular team meetings. We anticipate an improved understanding of the Neoproterozoic Earth system and the co-evolutionary interplay between the biosphere and planet.